1. Field of The Invention
The present disclosure relates to a light control device including a light control member including first portions and second portions are alternately arranged.
2. Description of Related Art
As disclosed in JP2006-222011A, there is known a light control device or a daylighting device including a light control member to be disposed on a window member, the light control member including first portions and second portions that are alternately arranged. The light control member of such a light control device exerts a predetermined optical function on sunlight, due to reflection and refraction of an interface between the first portion and the second portion, or owing to a functional substance contained in the first portion or the second portion.
For example, when the second portion contains a visible-light absorbing material, as in the light control member disclosed in JP2006-222011A, the light control member transmits light coming from a normal direction thereof, while the light control member shields visible light coming from a direction that is inclined upward to some extent relative to the normal direction. Namely, the light control member can exert a light shielding function from a viewpoint of anti-glare effect, by restraining direct sunlight from entering a room. Alternatively, when the second portion contains a heat-ray absorbing material, the light control member can exert a heat shielding function by shielding heat rays included in the sunlight coming from the direction that is inclined upward to some extent relative to the normal direction. Further, when the first portion and the second portion have different refractive indexes, the light control member can exert a daylighting function (letting-in-light function, improving-lighting function) for letting in the sunlight in a desired direction in the room, by reflecting sunlight coming from a predetermined direction to change a traveling direction thereof.
However, relative positions of the light control member and the sun vary depending firstly on a longitude and a latitude of a place where the light control member is installed, and/or an orientation at which the light control member is installed. Thus, normally, the arrangement, shapes, materials, etc. of the first portion and the second portion should be suitably set for each of the light control members that are installed in different places. Moreover, the relative positions of the light control member and the sun vary depending on seasons and hours. Thus, even when the light control member is designed in consideration of installation conditions, it is not sufficient. The light control member cannot sufficiently exert a function that is expected to be offered by the light control member, continuously through a whole year or even through a certain day.
If the light control member can exert the expected functions, such as the daylighting function, the light shielding function, the heat shielding function, etc., regardless of seasons and hours, the use of an illumination tool, an air conditioner or the like can be restrained whereby energy can be saved and CO2 can be reduced. However, in order that the light control member can sufficiently exert predetermined functions on sunlight regardless of seasons and hours, it is necessary to prepare light control members having different structures from one another, and to select and use a suitable light control member to be used depending on seasons and hours.